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Title: Electronic Structure of the Hydroxo and Methoxo Oxometalate Anions MO3(OH)- and MO3(OCH3)- (M=Cr, Mo, and W)

Abstract

The electronic structure of the mononuclear hydroxo MO3(OH)- and methoxo MO3(OCH3)- Group 6 oxometalate anions (M ) Cr, Mo, and W) were examined by photodetachment photoelectron spectroscopy and electronic structure calculations at the density functional and CCSD(T) levels of theory. All of the anions exhibited high electron binding energies (>4.9 eV), with the lowest-energy detachment features arising from oxygen 2p-based orbitals. The combined experimental and theoretical results allowed the change in molecular orbital energy levels to be investigated as a function of metal (Cr, Mo, or W) and ligand (-OH, -OCH3). A number of fundamental thermodynamic properties of the anions and corresponding neutrals were predicted on the basis of the theoretical calculations. The calculations indicate high O-H bond dissociation energies for MO2(OR)(O-H) (R ) H, CH3) and MO3(O-H), consistent with their high Brønsted acidities (just below that of H2SO4 in the gas phase) and the high ionization energies of their conjugate base anions. This suggests that the corresponding radicals should readily abstract H atoms from organic molecules.

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
877005
Report Number(s):
PNNL-SA-48098
Journal ID: ISSN 1089-5639; JPCAFH; 3565; 3568; KC0301020; TRN: US200608%%240
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Physical Chemistry A, 109(51):11771-11780; Journal Volume: 109; Journal Issue: 51
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ELECTRONIC STRUCTURE; ENERGY LEVELS; DENSITY FUNCTIONAL METHOD; PHOTOELECTRON SPECTROSCOPY; THERMODYNAMIC PROPERTIES; CHROMIUM COMPLEXES; MOLYBDENUM COMPLEXES; TUNGSTEN COMPLEXES; Environmental Molecular Sciences Laboratory

Citation Formats

Waters, Tom, Wang, Xue B., Li, Shenggang, Kiran, Boggavarapu, Dixon, David A., and Wang, Lai S.. Electronic Structure of the Hydroxo and Methoxo Oxometalate Anions MO3(OH)- and MO3(OCH3)- (M=Cr, Mo, and W). United States: N. p., 2005. Web. doi:10.1021/jp054666x.
Waters, Tom, Wang, Xue B., Li, Shenggang, Kiran, Boggavarapu, Dixon, David A., & Wang, Lai S.. Electronic Structure of the Hydroxo and Methoxo Oxometalate Anions MO3(OH)- and MO3(OCH3)- (M=Cr, Mo, and W). United States. doi:10.1021/jp054666x.
Waters, Tom, Wang, Xue B., Li, Shenggang, Kiran, Boggavarapu, Dixon, David A., and Wang, Lai S.. Thu . "Electronic Structure of the Hydroxo and Methoxo Oxometalate Anions MO3(OH)- and MO3(OCH3)- (M=Cr, Mo, and W)". United States. doi:10.1021/jp054666x.
@article{osti_877005,
title = {Electronic Structure of the Hydroxo and Methoxo Oxometalate Anions MO3(OH)- and MO3(OCH3)- (M=Cr, Mo, and W)},
author = {Waters, Tom and Wang, Xue B. and Li, Shenggang and Kiran, Boggavarapu and Dixon, David A. and Wang, Lai S.},
abstractNote = {The electronic structure of the mononuclear hydroxo MO3(OH)- and methoxo MO3(OCH3)- Group 6 oxometalate anions (M ) Cr, Mo, and W) were examined by photodetachment photoelectron spectroscopy and electronic structure calculations at the density functional and CCSD(T) levels of theory. All of the anions exhibited high electron binding energies (>4.9 eV), with the lowest-energy detachment features arising from oxygen 2p-based orbitals. The combined experimental and theoretical results allowed the change in molecular orbital energy levels to be investigated as a function of metal (Cr, Mo, or W) and ligand (-OH, -OCH3). A number of fundamental thermodynamic properties of the anions and corresponding neutrals were predicted on the basis of the theoretical calculations. The calculations indicate high O-H bond dissociation energies for MO2(OR)(O-H) (R ) H, CH3) and MO3(O-H), consistent with their high Brønsted acidities (just below that of H2SO4 in the gas phase) and the high ionization energies of their conjugate base anions. This suggests that the corresponding radicals should readily abstract H atoms from organic molecules.},
doi = {10.1021/jp054666x},
journal = {Journal of Physical Chemistry A, 109(51):11771-11780},
number = 51,
volume = 109,
place = {United States},
year = {Thu Dec 29 00:00:00 EST 2005},
month = {Thu Dec 29 00:00:00 EST 2005}
}